Technics SUV 550 Service Manual

Page 2

I CONTENTS

Page
BEFORE REPAIR AND ADJUSTMENT ...................... 2
PROTECTION CIRCUITRY ................................ 2
ACCESSORY ............................................ 2
LOCATION OF CONTROLS .............................. 3, 4
CONNECTIONS ........................................ 5, 6
DISASSEMBLY INSTRUCTIONS .......................... 7, 8
CIRCUIT BOARDS AND
WIRING CONNECTION DIAGRAM .................... 9~11

Page
TERMINAL GUIDE OF ICS.

TRANSISTORS AND DIODES .......................... 12
SCHEMATIC DIAGRAM .............................. 13~ 16
BLOCK DIAGRAM .................................... 17, 18
MEASUREMENTS AND ADJUSTMENTS .................. 19
REPLACEMENT PARTS LIST ...................... 19, 20, 23
EXPLODED VIEW .................................... 21, 22
RESISTORS AND CAPACITORS ........................ 24, 25

I BEFORE REPAIR AND ADJUSTMENT

(1) Turn off the power supply. Using a 100, 10W resistor, shortcircuit both ends of power supply capacitors

(C705.C706)in order to discharge the voltage.

(2) Before turning on the power switch of the unit.

A. Connect the voltage controller to the primary side.

B. Connect the AC ampere meter to the primary side or connect the DC voltage meter to the 1:8 circuit

of the secondary side.

C. Turn the VR of ICO(VR401 and VR402)to minimum(counterclockwise).

D. After setting the output to zero of the voltage contoller,turn on the power switch of the unit.

And increase the output of voltage controller gradually.

Then, check carefully whether the current value of primary side become more than following value or

whether the DC voltage of secondary side is increasing slowly.

E. If the value of current is increasing unusually or the DC voltage is not increasing,lower the output

level of voltage contoller immediately.

0 The current value of the primary side at no signal. (Confirm the power supply voltage of each area and provided

voltage of the unit.)

Power supply voltage m

Consumed current 50/60Hz 280 ~ 560mA

I PROTECTION CIRCUITRY

The protection circuitry of the amplifier may have
operated if either of the following conditions is noticed:
o No sound is heard when the power is turned on.

0 Sound stops during a performance.

The function of this circuitry is to prevent circuitry damage

if, for example, the positive and negative speaker

connection wires are shorted , or if speaker systems with

an impedance less than the indicated rated impedance
of the amplifier are used.

I ACCESSORY

OAC power supply cord ...................... 1
(SJA168) .................. For (XA) area only.
(SJA173) .................. For (XL) area only.
(SJA193) .................. For (EK) area only.
(SFDACOSE03) .................... For others.

260 ~ 520mA

AC1 27V

AC220V ' AC240V
140 ~ 280mA 130 ~ 260mA

If this occurs, follow the procedure outlined below:
1.Turn off the power.

2.Determine the cause of the problem and correct it.
3.Turn on the power once again.

Note:

When the protection circuitry functions. theunit will not
operate unless the power is first turned off and then

on again.